1. Field of the Invention
The present invention relates, in general, to an optical switch using polarization control of light and a method thereof; and more particularly to a technology that combines plasmonic electromagnetically induced transparency (EIT) and polarization hybridization to provide an optical switch by using a voltage-controlled Pockels cell to rotate the polarization of a passing beam.
2. Description of the Related Art
An optical switch is a switch that enables signals in optical fibers or integrated optical circuits to be selectively switched from one circuit to another, which is a key component in an optical network. The optical switch based on nonlinear optical effect has received much attention; however, it is only to a limited extent depending on a device size and light intensity thereof.
It is found that electromagnetic fields can be localized by utilizing a defect of photonic crystals, thereby enhancing nonlinearity effects (see Zayats, Phys. Rep. Vol. 408, pp. 131-314, 2005). Also, Nozaki et al. proposed combining an ultrasmall photonic-crystal nanocavity and strong carrier-induced nonlinearity in InGaAsP to produce the optical switch (see Nozaki, Nat. Photonics Vol. 4 pp. 477-483, 2010). Further, the excitation of surface plasmon polaritons can alternatively be used to localize the electromagnetic fields. For instance, Large et al. proposed a new concept of ultrafast optical switches based on nonlinear plasmonic nanoantennas (see Large, Nano Lett. Vol. 10, pp. 1741-1746, 2010). The prior art methods described in the above, although being based on different principles and mechanisms, share a common technique to shift a resonant frequency by using another coupling beam to switch a pathway of a passing beam.
Electromagnetically induced transparency (EIT) proposed by Harris has been intensively studied due to its various applications such as for slow light or optical switches, in the field of photon information processing. The EIT, as a direct result of quantum destructive interference between alternative pathways, renders an ultra low absorption (see Harris, Phys. Today Vol. 50, pp. 36, 1997). Zhang et al. proposed the plasmonic EIT in metamaterials in 2008 (see Zhang, Phys. Rev. Lett. Vol. 101, pp. 047401, 2008), which is experimentally realized in 2009 (see Liu, Nat. Mater. Vol. 8, pp. 758-762, 2009). In the metamaterials, a plasmonic interaction in a near-field zone replaces the role of a coupling beam in the conventional EIT. The coupling becomes intrinsically induced and are not selectively excited and therefore, it is no longer suitable for the optical switch.